MAJOR fixes:
- Remove external YAML dependency (github.com/goccy/go-yaml)
Per project convention: Go standard library only, zero dependencies.
Convert all persona files from YAML to JSON format.
- Fix TestValidateWorkspacePath error expectation
Go 1.21+ filepath.Join normalizes absolute paths differently.
MINOR fixes:
- Remove custom contains helper in persona_test.go (use strings.Contains)
- Add Unicode-safe CapitalizeFirst function for header titles
- ListBuiltinPersonas returns empty slice instead of nil on error
- Fix test comment about filepath.Join behavior
Documentation:
- Update README to reflect JSON-only persona format
- Update design doc with note about JSON decision
- Fix action.yml description for persona-file input
Add persona system for specialized review roles. Each persona defines:
- A specific review focus (security, architecture, documentation)
- Custom system prompt additions
- Personality/tone adjustments
Built-in personas: security, architect, docs
Custom personas: load from JSON via persona-file flag
Includes workspace validation to prevent path traversal attacks.
Closes#51